Method of preparing subsurface and forming concrete column therein



M. H. SCHUTTE METHOD OF PREPARING SUBSURFACE AND FORMING CONCRETE COLUMN THEREIN June 29, 1965 2 Sheets-Sheet 1 Filed Dec. 2, 1960 m f. u 0 C J a J m, M

IN VEN TOR.

147' 7 O/P/VE VJ M. H. SCHUTTE METHOD OF PREPARING SUBSURFACE AND FORMING CONCRETE COLUMN THEREIN June 29, 1965 2 Sheets-Sheet 2- Filed Dec. 2, 1960 My/eJ f2. Jc/fiuf/e INVENTOR.

ATTORNEYJ United States Patent 3,191,390 METl-EQD 0F PREPARING SUBSURFACE AND FGENG CONCRETE CQLUMN THEREIN Myles H. Sehutte, Houston, Tex., assignor to Bell Bottom Foundation Co, Houston, Ten, a corporation of Texas Filed Dec. 2, 1960, Ser. No. 7 3,285

2 Claims. (Cl. til-53.6)

This invention relates to new and improved methods of preparing the subsurface for forming foundation members therein and for forming foundation members in the ground or subsurface.

An object of this invention is to provide new and improved methods of forming foundation members in the ground or subsurface, and particularly in ground or subsurface in which it would normally be difiicult or impossible to maintain a bore wall when drilling the bore or hole for the foundation member.

An important object of this invention is to provide a new and improved method of forming a bore hole by drilling in the subsurface while preventing the wall of such bore hole from collapsing both during drilling and thereafter even though the subsurface is sandy or is otherwise of such a nature that it would collapse with conventional methods heretofore used.

Another object of this inventionisto provide a new and improved method of drilling a bore hole in a subsurface for subsequently pouring a concrete foundation member in such hole, wherein the bore hole is filled with mud or other liquid during drilling, concrete is mixed with such mud or liquid after drilling the hole, and then anew hole is drilled in the concrete and mud mixture after such mixture hardens which new hole is smaller in diameter than the original bore hole, whereby a retaining Wall of the hardened mixture of concrete and mud is left in the hole to prevent collapse of the wall of such hole.

A further object of this invention is to provide a new and improved method of drilling a bore hole in a subsurfacewherein a plurality of wells are initially drilled around the area in which said bore holes is to be drilled for the purpose of dewatering said area priorto drilling said bore hole so that the tendency of the wall of said bore hole to collapse is inhibited.

Still another object of this invention is to provide a new and improved method of forming a foundation member or column in a subsurface wherein the hole for the foundation member is maintained with liquid therein during drilling, and wherein the liquid is displaced from the hole after drilling by concrete forming the foundation member which is introduced starting at the bottom of step in the method of this invention which involves the drilling of the bore hole, preferably with the prior drilling of wells adjacent thereto;

FIG. 2 illustrates the second step in the process of this invention which includes the underreaming of the bore hole;

FIG. 3 is a view illustrating the third step in the method of this invention which includes the addition of cement or concrete and possibly other additives to the drilling fluid while mixing same together to form a hardened structure within the bore;

FIG. 4 is a vertical sectional view illustrating the hardened material in the bore hole;

FIG. 5 is a vertical sectional view illustrating the next step in the method of this invention which includes the drilling out of the bore hole to a smaller diameter than the original bore hole, leaving an annular wall of the hardened material in the bore hole;

FIG. 6 is a vertical sectional view illustrating the underreaming of the hardened body which is preferably carried out in the method of this invention;

FIG. 7 is a vertical sectional view illustrating the final step in the method of this invention wherein concrete or the like is poured into the bore hole having the annular wall of the reinforcing material formed therein;

FIG. 8 is a vertical sectional view illustrating one step in an alternative method of this invention; and

FIG. 9 is a vertical sectional view illustrating another step in the alternative method of this invention.

Briefly, the method of this invention involves the drilling of a hole B for a foundation member in the ground or subsurface G while maintaining a level of mud or liquid M in the hole B during such drilling to prevent the walls of such hole B from collapsing even the soil forming the subsurface G is sandy or of such a nature that it would normally collapse when using conventional methods of drilling holes for foundation members. Additionally, the method of this invention includes the pouring of cement or concrete into the liquid M as indicated at C (FIG. 3) for forming a hardened solid column of the cement or concrete and the liquid M in the bore hole B. When the cement or concrete C is mixed with the mud or liquid M, the method of this invention includes the drilling of a final bore hole H (FIG. 5) into the hardened solid column in the bore hole B so as to leave an annular retaining wall R in the bore hole B for preventing the collapse of the walls of such bore hole B and for also sealing the interior of the hole H from intrusion by fluids in the subsurface G. The concrete forming the foundation member F (FIG. 7) is subsequently poured into the final bore hole H and is extended above the ground surface S in any conventional way.

Considering the method of this invention more in detail, the preferred form of the invention is illustrated in FIGS. 1-7 schematically. In carrying out such preferred form of the method of this invention, a plurality of wellsW are drilled in the subsurface G surrounding a central area C.

The location of the wells W around the central area C of the subsurface G provides for the dewatering or draining of such central area C of water or other liquid which normally would be present in such subsurface G. In that way, the central area C of the subsurface G is dried so as to render thesoil or other substance making up the subsurface G more stable. This is particularly desirable in sandy soils or other subsurface substances which normally tend to collapse when a hole is drilled in such subsurface G.

After the wells W are drilled in suitable number to dewater the central area C, the bore hole B is drilled with a conventional drilling tool T which as shown includes an anger blade 10 which is rotated by any suitable drill pipe of support 11 extending from above the surface S. Upon a rotation of the drilling tool T, the auger blade 10 cuts the bore hole B in the known manner. The drilling mud or liquid M is fed into the bore hole B during the drilling thereof to maintain a level of such drilling mud or liquid M sufficiently high to prevent the collapse of the walls of the bore hole B during the drilling thereof. In most instances, the level of the mud or liquid M will be at substantially the surface S so that such bore hole B is preferably full of the mud or liquid M to prevent the collapse of the walls thereof. As the cuttings of soil or other subsurface substance are removed during the drilling of the bore hole B, they remain in the bore hole B and are mixed with the mud or liquid M to increase the density or thickness of such liquid M. In the event the thickness or density of the liquid M becomes too great, some of the liquid M may be removed by bailing and then the liquid may be diluted by the addition of water or other drilling liquid.

After the bore hole B is drilled to the desired depth with the drilling tool T as illustrated in FIG. 1, then the bore hole B is preferably underreamed with a conventional underreaming tool U to form an enlarged flared portion E in the bore hole B. During such underreaming with the underreamer tool U, the level of the drilling mud or liquid M is maintained, preferably full, to prevent the collapse of the Walls of the bore hole B and the enlarged portion E. Also, as previously explained in connection with FIG. 1, the presence of the plurality of water wells W surrounding the bore hole B assists in maintaining the subsurface G solidified and in preventing the walls of the bore hole B from collapsing during the underreaming operation illustrated in FIG. 2.

After the underreaming step is completed as illustrated in FIG. 2, the underreamer tool U is withdrawn, leaving the liquid M in the bore hole B. Thereafter, the cement or concrete C is introduced into the liquid M and to facilitate the mixing of the cement or concrete C with the liquid M, the drilling tool T is positioned in the bore hole B and is rotated and also it may be reciprocated. In that Way, the cement or concrete and the mud or liquid M are mixed together to form a hardenable mixture. A hardening accelerator agent such as calcium chloride is introduced with the cement to increase the setting time. The quantity of the'accelerator varies depending upon the thickness of the mixture of the cement and the liquid M, and also upon the percentage of the cement which is introduced into the bore B as compared to the amount of the liquid M already in the bore B. In the preferred form of the invention, the liquid M is a mud such as bentonite mixed with water for fluidity. As is well known, bentonite is a hydrous silicate of alumina which is comprised principally of the clay mineral montrnorillonite, and when mixed with water, it swells and forms a viscous gel. When using such a viscous gel, such as bentonite provides, as the liquid M, the cement is preferably added in quantities of from about one to about three hundred pounds per each yard of volume of the hole B, or stated differently, per yard of volume of the mixture of liquid -M and cement C. The calcium chloride accelerator agent is added in a volume percentage of about 1% to about 40% of the cement used. If accelerator agents other than calcium chloride are used, the percentage may of course vary.

The underreamer tool U may also be used for agitating the mixture of the cement or concrete C and the liquid M in the enlarged portion E of the bore hole B. After the mixture of the cement or concrete C with its hardening accelerator agent and the liquid M have been adequately mixed as illustrated in FIG. 3, the mixture is allowed to harden to form a solid column SC in the bore hole B and the enlarged portion E thereof. Such column SC would normally not have sufficient strength to serve as the foundation member or column itself since it has a considerable amount of the mud mixed therewith. After the solid column SC has hardened, which normally takes approximately twenty-four hours, the final bore 'hole H is drilled in the solid column SC leaving the retainer wall R (-FIG. 5). The drilling of the final bore hole H is accomplished with a drilling tool T which is preferably of the same type as was used for the drilling of the first or original bore hole B. However, other types of drilling tools may be utilized, but in any event, the drilling tool I used in drilling the final bore hole H,would drill a bore hole of a smaller diameter than the original bore hole B so as to leave suchannular retaining wall R which is made up of the hardened mixture of the concrete and the mud or liquid M. By reason of the retaining wall R, the wall of the bore hole B is prevented from collapsing and also a seal against the ingress of water or other fiuid from the surrounding subsurface G is reduced or inhibited.

After the final bore ho-le H is drilled to the desired depth in the solid column SC, an underreamer tool U which may be of the same construction as the underrearner tool U used originally in the underreaming of the enlarged portion E is used for underreaming an enlarged portion H in the final bore hole H. The diameter of the underreamed portion H is smaller than the diameter of the underreamed portion B so as to again leave a retaining wall R in the enlarged portion E of the bore hole B. Such retaining wall R serves the same purpose as the retaining wall R of which it is a part.

After the final hole H and the enlarged portion H thereof has been formed, concrete of the usual consistency is poured into such hole H to form the foundation member F in the usual manner. The foundation member F preferably would extend above the upper surface S of the subsurface G by the use of casings of metal or other similar forming members in the conventional manner. By reason of the method of this invention as previously described, the foundation member F may be poured in sandy or soft soil or subsurface in which it would otherwise be necessary to drive piling rather than form concrete foundation members therein.

Certain steps in an alternate form of the method of this invention are illustrated in FIGS. 8 and 9 of the drawings. In carrying out such modified form of the invention, the steps illustrated in FIGS. 1 and 2 of the drawings are preferably performed first. It should be noted however that the drilling of the wells W is not always desirable or necessary and therefore may be omitted. Also, in carrying out the modified form of the invention, the bore hole B which is drilled is of the final diameter desired for the foundation member. As noted previously, the bore hole B is larger in diameter than the .final diameter of the hole H and is therefore larger than the diameter of the foundation member Such is not the case in connection with the modified form of the invention since the annular retaining wall R is not formed in the modified form of the invention.

During the drilling of the bore hole B in the ground or subsurface G with a drilling tool T and with an underreamer tool U, the mud or liquid M is maintained at a level which is sufficient to prevent the collapse of the walls of such bore hole B. Normally, as explained in connection with the preferred form of the invention, the

level of the liquid or mud M would be at the surface S so that the bore hole B would be filled with such liquid M.

After the bore hole B has been drilled and underreamed to form the enlarged portion E therein, a casing or pipe 15 formed of steel or other similar material and which has a removable bottom plate 16 is lowered into the liquid M. The removable bottom plate 16 is held in a closed position in contact with the lower edges of the casing or pipe 15 by means of a cable 20 which extends to the area above the sunface S for control by an operator. During the lowering of the casing 15 into the liquid M, such casing :15 is filled, or partially filled with cement or concrete C which also would include the accelerator agent such as calcium chloride as explained in connection with the first form of the invention. However, in view of the fact that the concrete C in the alternate or modified form of the invention of FIGS. 8 and 9 is not diluted to the extent that it is in connection with the first form of the invention of FIGS. l-7, the amount of the accelerator agent is more nearly the normal amount used in concrete work.

A wire frame of reinforcing wires including a plurality of longitudinally extending wires 22 and annular or circular wires 23 which are secured or welded together is formed and is positioned in the liquid M, either before the casing is lowered into the liquid M, or thereafter. The wires 22 and 2.3 surround the casing 1 5 after they are in position. The reinforcing frame of the wires 22 and 23 is made from the usual reinforcing steel rods but may of course be made from other suitable reinforcing material.

After the casing 15 with its concrete C and the reinforcing frame of reinforcing rods 22 and 23 have been positioned in the bore hole B, a pulling force is applied upwardly to the cable or wire of sufficient amount to break such cable or wire 20 to release it from the bottom plate 16. At the time of such release of the cable or line 20 from the releasable plate or cover 16, the cover 16 is preferably on the bottom of the bore hole B as shown in FIG. 8. Then, the casing 15 is lifted upwardly several feet so that the concrete C gradually is discharged from the lower end of the casing 15 into the bore hole B. Since the concrete C is heavier than the mud or liquid M, the concrete C displaces the mud or liquid M upwardly. It is to be noted that the removable plate 16 remains at the bottom of the bore hole B since it has been disconnected from the casing 15 as previously explained.

The casing 15 is gradually raised upwardly in the bore hole B and therefore the concrete C is gradually discharged from the lower end of the casing 15 into the bore hole B to continue the displacement of the liquid M upwardly and to continue to fill the bore hole B with the concrete C from the bottom to the top thereof. Additional concrete C may be introduced into the casing 15 if necessary to supply enough concrete to fill the bore hole B. The casing 15 is of course raised upwardly until it is completely withdrawn from the bore hole B, and at that time, the bore hole B is filled with the concrete C to form a solid column without any appreciable mixture of the concrete C with the liquid or mud M. In some instances, the usual type of steel casing or form for foundation members is positioned above the surface S and forms an upward extension of the hole B in the usual way to provide for the extension of the foundation member upwardly above such surface S. In any event, the foundation member is thus formed without the drilling of the additional hole H which is drilled in the form of the invention shown in FIGS. 1-7.

The advantages and features of the method of this invention are believed evident from the foregoing description. It will be appreciated by those skilled in the art that variations and modifications in the method of this invention as described herein may be made without departing from the scope of this invention.

What is claimed is:

1. A method of forming a concrete column in the soil comprising the steps of:

drilling into the subsurface with a drill bit to drill a bore hole,

introducing drilling liquid including water into the bore hole during drilling to maintain a level of liquid for substantially the full depth of the bore hole as it is drilled to prevent collapse of the walls of the bore hole, removing some of the cuttings made by the drill bit during drilling to reduce the thickness of the liquid in the bore hole,

thereafter introducing cement into the liquid in the bore hole separately from the drill bit,

thereafter rotating and longitudinally reciprocating the drill bit in the liquid to thoroughly mix the cement, water and soil in the bore hole,

thereafter removing the drill bit from the bore hole to allow the cement, water and soil to harden to become a hardened column in the soil,

subsequently drilling a bore in the hardened column of a smaller diameter than the hardened column so as to leave an annular wall thickneses of the hardened column around the smaller diameter bore, and

thereafter introducing concrete into the smaller diameter bore to form a concrete column therein.

2. A method of forming a concrete column in the soil comprising the steps of,

drilling into the subsurface with a drill bit to drill a bore hole,

introducing drilling liquid including water into the bore hole during drilling to maintain a level of liquid for substantially the full depth of the bore hole as it is drilled to prevent the collapse of the walls of the bore hole,

underreaming the bottom of the bore hole with an underreamer tool While continuing to maintain a level of liquid in the bore to prevent collapse of the walls of the bore hole,

thereafter introducing cement into the liquid in the bore hole separately from the drill bit,

thereafter removing the drill bit from the bore hole to allow the cement, water and soil to harden to become a hardened column with an underreamed bottom,

subsequently drilling a bore in the hardened column of a smaller diameter than the hardened column so as to leave an annular wall thickness of the hardened column around the smaller diameter bore,

underreaming at the bottom of the smaller diameter bore at the same level as the underreamed hole but of a reduced diameter so as to leave a wall thickness of the hardened material, and

thereafter introducing concrete into the underreamed bore and the smaller diameter bore to form a concrete column with a flared base in the soil.

References Cited by the Examiner UNITED STATES PATENTS 1,591,165 7/26 Hesse 61-53.6 X 1,888,282 11/32 Miller 6l-53.6 1,909,980 5/33 Newman 61-39 2,412,239 12/46 Weber 61-535 X 2,782,605 2/57 Wertz et al 61-36 2,791,886 5/57 Veder 61-50 X 2,875,584 3/59 Turzillo 61-50 FOREIGN PATENTS 443,262 2/36 Great Britain.

OTHER REFERENCES The Chemistry of Cement and Concrete: 2nd edition, 1956, by Lea and Desch; p. 252; pub. by Edward Arnold, London, England.

EARL J. WI] MER, Primary Examiner.

JACOB L. NACKENOFF, Examiner. 

1. A METHOD OF FORMING A CONCRETE COLUMN IN THE SOIL COMPRISING THE STEPS OF; DRILLING INTO THE SUBSURFACE WITH A DRILL BIT TO DRILL A BORE HOLE, INTRODUCING DRILLING LIQUID INCLUDING WATER INTO THE BORE HOLE DURING DRILLING TO MAINTAIN A LEVEL OF LIQUID FOR SUBSTANTALLY THE FULL DEPTH OF THE BORE HOLE AS IT IS DRILLED TO PREVENT COLLAPSE OF THE WALLS OF THE BORE HOLE, REMOVING SOME OF THE CUTTINGS MADE BY THE DRILL BIT DURING DRILLING TO REDUCE THE THICKNESS OF THE LIQUID IN THE BORE HOLE, THEREAFTER INTRODUCING CEMENT INTO THE LIQUID IN THE BORE HOLE SEPARATELY FROM THE DRILL BIT, THEREAFTER ROTATING AND LONGITUDINALLY RECIPROCATING THE DRILL BIT IN THE LIQUID TO THROUGHLY MIX THE CEMENT, WATER AND SOIL IN THE BORE HOLE, THEREAFTER REMOVING THE DRILL BIT FROM THE BORE HOLE TO ALLOW THE CEMENT, WATER AND SOIL TO HARDEN TO BECOME A HARDENED COLUMN IN THE SOIL, SUBSEQUENTLY DRILLING A BORE IN THE HARDENED COLUMN OF A SMALLER DIAMETER THAN THE HARDENED SO AS TO LEAVE AN ANNULAR WALL THICKNESS OF THE HARDENED COLUMN AROUND THE SMALLER DIAMETER BORE, AND THEREAFTER INTRODUCING CONCRETE INTO THE SMALLER DIAMETER BORE TO FORM A CONCRETE COLUMN THEREIN. 